The chaos of Iraq is giving rise to a new generation of "professional" terrorists who will eventually replace al-Qaida as a global threat, according to a CIA thinktank.

A report by the National Intelligence Council says the war in Iraq has provided a training and recruitment ground for Islamist militants, much as Afghanistan did for the founding generation of al-Qaida during the war against the Soviet occupation in the 1980s.

As new terror organisations emerge on the world stage, al-Qaida will splinter into regional separatist groups, says the report, which forecasts global trends over the next 15 years.

"Iraq and other possible conflicts in the future could provide recruitment, training grounds, technical skills and language proficiency for a new class of terrorists who are 'professionalised' and for whom political violence becomes an end in itself," the report says.

It gives warning that veterans of the conflict in Iraq could disperse around the world, exporting their deadly expertise.

Specifically, the report warns that the US faces an increasing risk of an attack involving biological agents, such as anthrax, and that an emerging and more sophisticated generation of terrorists could also use chemical weapons.

The bleak forecast undermines one of the Bush administration's central justifications for invading Iraq: that it was necessary to curb terrorism; that the country was a central front in the "war on terror"; and that the deposed Iraqi dictator, Saddam Hussein, had links to al-Qaida's chief, Osama bin Laden.

Instead, the report describes how hundreds of foreign terrorists entered Iraq after the US invasion, and how the insurgency against American forces was viewed by radical Muslims as a war against a foreign occupier, akin to the Israeli-Palestinian conflict.

Terrorists also took advantage of postwar chaos, porous borders and a country awash with weapons.

But unlike the rise of al-Qaida in Afghanistan, the emerging terrorists do not require a geographical base, and are expected to rely increasingly on the internet.

"While taking advantage of sanctuaries around the world to train, terrorists will not need a stationary headquarters to plan and carry out operations," the report says.

The terrorists now recruited and trained in Iraq will eventually become the successor generation to al-Qaida, it predicts. "Al-Qaida membership that was distinguished by having trained in Afghanistan will gradually dissipate, to be replaced in part by the dispersion of the experienced survivors of the conflict in Iraq."

The 119-page report was based on analysis from more than 1,000 US and foreign observers, and is designed to help the White House track world trends up to 2020.

· Staff Sergeant Cardenas Alban was sentenced at a court martial yesterday to a year in jail for the murder of a severely wounded Iraqi teenager in a Baghdad slum district during a Shi'ite uprising last year, the US military said.